1. Field of the Invention
The present invention relates to an optical receptacle for coupling a connector ferrule in which an optical fiber is inserted and an optical semiconductor package to each other and, more particularly, to a highly reliable optical receptacle capable of obtaining a low-reflection condition with stability.
2. Background Art
An optical receptacle is used to couple a connector ferrule in which an optical fiber is inserted and an optical semiconductor package in which a photodiode (PD) chip or a laser diode (LD) chip is mounted.
In conventional optical receptacles, light emitted from a connector ferrule is directly coupled to a PD chip in an optical semiconductor package. However, the tip of the connector ferrule is floating in the air and there is, therefore, a problem that light traveling from a transmitter via the connector ferrule is largely reflected to the transmitter side at the tip end surface of the connector ferrule due to the difference between the refractive indices of air and the optical fiber.
In recent years, an optical receptacle has been proposed in which the tip end surface of a connector ferrule is brought into contact with a transparent plane-parallel plate (see, for example, Japanese Patent Laid-Open Nos. 1-109313 and 64-52103). The reflection of light at the tip end surface of a connector ferrule can be reduced in this way.